1. Field of the Invention
The present invention relates to a communication device used in a wireless communication system, and more particularly, to a communication device of handling network configurations in a wireless communication system.
2. Description of the Prior Art
A long-term evolution (LTE) system is developed by the 3GPP as a successor of the universal mobile telecommunication system (UMTS) for further enhancing performance of the UMTS to satisfy increasing needs of users. In the LTE system, a radio access network known as an evolved universal terrestrial radio access network (E-UTRAN) includes at least one evolved Node-B (eNB) for communicating with at least one user equipment (UE), and for communicating with a core network including a mobility management entity (MME), a serving gateway, etc., for Non-Access Stratum (NAS) control.
A LTE-advanced (LTE-A) system is an evolution of the LTE system. The LTE-A system improves performance at the coverage edge of an eNB, increases peak data rate and throughput by using advanced techniques such as carrier aggregation (CA), coordinated multipoint (CoMP) transmissions/reception, etc.
The UE may receive/transmit packets (e.g., transport blocks (TBs)) from/to two eNBs, when the UE is configured with a dual connectivity. Throughput of the UE is improved when the dual connectivity is operated. However, it is not clear how to perform a reconfiguration of a radio link control (RLC) configuration (i.e., rlc-config), a packet data convergence protocol (PDCP) configuration (i.e., pdcp-config) and/or a semi-persistent scheduling (SPS) configuration (i.e., sps-config) which is configured for a master cell group (MCG) and/or a secondary cell group (SCG) according to the dual connectivity.
On the other hand, according to the prior art, when a UE changes a primary secondary cell (PSCell) of a secondary eNB (SeNB) from a cell of the SeNB to another cell of the SeNB, or perform a handover from a master eNB (MeNB) to the SeNB, the UE resets a header compression/decompression protocol for a header compression/decompression of a radio bearer with a SCG bearer type. In other words, the UE reestablishes or resets a context for the header compression/decompression of PDCP service data units (SDUs) of the radio bearer. That is, the UE starts with an initialization & refresh (IR) state in U-mode in the header compression. The UE starts with no context state in the header decompression. Thus, efficiency of the header compression/decompression is decreased.